Field of the Invention
The present invention relates to the use of certain compounds [Compounds (A)] for the treatment of crop plants for inducing specific growth regulating responses on the plants, on seeds from which they grow or on the locus in which they grow in their normal habitat, preferably in the absence of extraordinary environmental conditions.
The term “method for plant growth regulation” or the term “growth regulation process” or the use of the words “plant growth regulation” or other terms using the word “regulate” as used in instant specification relate to a variety of plant responses that improve some characteristic of the plant. “Plant growth regulators” are compounds which possess activity in one or more growth regulation process(es) of a plant. Plant growth regulation is distinguished here from pesticidal action or growth reduction, sometimes also defined as a plant growth regulation, the intention of which, however, is to destroy or stunt the growth of a plant. For this reason, the compounds used in the practice of this invention are used in amounts which are non-phytotoxic with respect to the plant being treated but which stimulate the growth of the plant or certain parts thereof. Therefore, such compounds may also be called “plant stimulants”, their action may be named “plant growth stimulation”.
Plant growth regulation is a desirable way to improve plants and their cropping so as to obtain improved plant growth and better conditions in agriculture practice compared to non-treated plants. These kinds of molecules can either inhibit or promote cellular activities. This means that plant growth regulators identified in plants most often regulate division, elongation and differentiation of plant cells in a way that, most often, they have multiple effects in plants. The trigger event can be seen to be different in plants in comparison to the one known from animals.
Description of Related Art
On the molecular level, plant growth regulators may work by affecting membrane properties, controlling gene expression or affecting enzyme activity or being active in a combination of at least two of the before mentioned types of interaction. Plant growth regulators are chemicals either of natural origin, also called plant hormones (like non-peptide hormones e.g. auxins, giberrellins, cytokinins, ethylene, brassinosteroids or abscisic acid, and salicilic acid), lipooligosaccharides (e.g. Nod factors), peptides (e.g. systemin), fatty acid derivatives (e.g. jasmonates), and oligosaccharins (for review see: Biochemistry & Molecular Biology of the Plant (2000); eds. Buchanan, Gruissem, Jones, pp. 558-562; and 850-929), or they can be synthetically produced compounds (like derivatives of naturally occurring plant growth hormones, ethephon). Plant growth regulators which work at very small concentrations can be found in many cells and tissues, but they seem to be concentrated in meristems and buds.
The mode of action of existing plant growth regulators is often not known. Various targets are discussed and among those, most of the affected molecules are involved in cell division regulation, like arresting the cell cycle in stage G1 or G2, respectively, others for signaling drought stress responses (Biochemistry & Molecular Biology of the Plant (2000); eds. Buchanan, Gruissem, Jones, pp. 558-560). In any case, the hormone control can be identified as an extremely complex cascade of up and down regulations which, for example, can lead to a growth stimulation of one organ or cell typus of a plant but also can lead to a repression in other organs or cell types of the same plant.
In many cases, kinases are involved either directly or indirectly in plant hormone control and among the kinases, protein kinases are central and highly specific control molecules in respect to cell cycle control. Such kinases are discussed as targets for several plant hormones, as it is the case for auxin and abscisic acid (Biochemistry & Molecular Biology of the Plant (2000); eds. Buchanan, Gruissem, Jones, pp. 542-565 and pp. 980-985; Morgan (1997), Annu. Rev. Cell. Dev. Biol., 13, 261-291; Amon et al. (1993), Cell, 74, pp. 993-1007; Dynlacht et al. (1997), Nature, 389, pp. 149-152; Hunt and Nasmyth (1997), Curr. Opin. Cell. Biol., 9, pp. 765-767; Thomas and Hall (1997), Curr. Opin. Cell Biol., 9, pp. 782-787). The preparation and use of 2-amino-6-oxypurine derivatives as plant growth regulators is described in WO20051117.
Since, however, the ecologic and economic demands on modern crop treatment compositions are increasing constantly, for example with respect to toxicity, selectivity, application rate, formation of residues and favourable manufacture, there is a constant need to develop novel crop treatment compositions which have advantages over those known, at least in some areas. It was therefore an object of the present invention to provide further compounds to be applied on plants, on seeds from which they grow or on the locus in which they grow in their normal habitat, for growth regulating responses, preferably in the absence of abiotic stress conditions. In this regard it should be mentioned that the term “absence of abiotic stress conditions” is to be understood in the context of the present invention to mean that plants or seeds are not exposed to extraordinary environmental conditions such as extreme drought, cold and hot conditions, osmotic stress, waterlogging, elevated soil salinity, elevated exposure to minerals, ozone conditions, strong light conditions, limited availability of nitrogen nutrients or limited availability of phosphorus nutrients, particularly extraordinary environmental conditions beyond normal environmental fluctuations that may occur under normal plant growing conditions. Growing in the absence of abiotic stress conditions thus encompasses growing plants in field conditions whereby the growing conditions, including nutrient supply, temperature, water supply, and other conditions are considered average to optimal for the particular crop species. Growing in the absence of abiotic stress conditions also encompasses growing plants under greenhouse conditions which are considered average to optimal for the crop species.
Generally, a superior growth may result in an improvement of growth, for example, with respect to:                germination,        root growth        shoot development,        sprouting,        flower development,        photosynthesis performance of the plants,        leaves growth, preferably growth of the area of leaves,        plants per area (improved plant density).        
Alternatively, the superior growth may result in an improvement of crop yield with respect to various parameters such as:                bio mass,        quantitative fruit yield,        size of fruits,        quantitative grain yield,        qualitative yield such as increase in content of desired components, e.g. sugar content of sugar beet or protein content in cereal grains, gluten content of grains for the production of glues).        
While the improvement in some of the above growth characteristics may be effected together, some may be achieved very specifically with no or even adverse effects on the other parameters.
It is thus desired to provide specific useful plant growth regulation effects on crop plants, that result in superior growth of these treated plants, certain parts of these plants or specific crop yield.
A broader group of compounds selected from the group of acylsulfonamides is described in WO-A-97/45016, WO-A-99/16744 and EP-A-365484 and references cited therein; the compounds hereinafter called “Compounds (A)”. From said publications it is known that the “Compounds (A)” have safener properties. Safeners are used in crops of useful plants together with pesticides, such as herbicides, insecticides or fungicides, preferably herbicides, to reduce phytotoxic effects of the pesticides on the crop plants. A good safener shall not reduce the desired effect of a pesticide on target organisms, for example the effect against weed plants in case of a herbicide as the pesticide. A commercial safener from Compounds (A) is cyprosulfamide (common name), hereafter also called “Compound (A1)”.
It is further known from WO 2007/062737 that such acylsulfonamide safeners have also shown effects to reduce plant damage of crop plants, specifically of maize plants, against certain abiotic stress such as extraordinary drought, heat or chillness.
According to WO 2010/003444 such acylsulfonamide safeners have also shown to improve root growth of crop plants, specifically of maize plants. Additionally, effects in regulating shoot growth of crop plants, specifically of maize plants, has been described in the reference too.
Additionally, effects were described for enhancing the action of some pesticides by the addition of acylsulfonamide safeners. So, WO 2008/131854 describes the enhancement of the action of the defoliant thidiazuron on cotton plants by the addition of cyprosulfamide. WO 2008/092615 describes the enhancement of the herbicidal action of the herbicide pinoxaden by the addition of cyprosulfamide.